There are several known techniques of producing a color image by a digital camera. Conventionally, color imaging is based on detecting three spectral ranges by filters respectively centered in the red (R), green (G) and blue (B) spectral zones.
One approach for acquisition of colored images, which became the industry standard, utilizes an arrangement of set of fixed color filters (i.e. color filter array (CFA)) which are placed in front of a monochrome sensor such that each pixel of the sensor measures the intensity of only one spectral component of the incident light, out of the three RGB components which are needed for producing a color image. For example, a Bayer's array is a specific CFA of this type, which is commonly used for acquisition of RGB images (see FIG. 1A). In order to produce a color image (in which each pixel contains information about all the three RGB components, the remaining two color components, which are not measured by the pixel, are calculated based on the values of these components measured by adjacent pixels. This process, known as “de-mosaicing”, may be performed by various well-known algorithms.
An alternative technique for acquisition of color images utilizes three monochromatic sensors and a spectral beam splitter component that splits the incident light, by its color, and directs three RGB components of the incident light to the three image sensors respectively. A system configured in accordance with this technique is illustrated in a self explanatory manner in FIG. 1C (image is taken from www.zeiss.de).
Yet an additional technique for acquisition of color images utilizes a color sensor in which each pixel is adapted for measuring all three RGB colors simultaneously, for example a Foveon® X3 sensor.